This mod is for anyone that is having problems with bolt cycling issues with EITHER the Threshold and G3 due to the Sail O-ring.

I got fed up with replacing the none standard O-ring (#3 Sail O-ring) on the bolt of my Threshold. First I was going to try and find my own source online, to the none standard O-ring. Rottensquad was kind enough to give me the size that DP uses for the Sail O-ring. Unfortunately I found out that this none standard O-ring to be difficult to locate. I was about to replace it with a 2 x 16mm O-ring as that's just slightly bigger than the stock and would be a usable substitute.
I tried a 2 x 16mm O-ring, I just so happen to have, and wal la. Fixed my bolt cycling problem. The problem was, that the bolt had tons of friction when cycling it. This would decrease the efficiency and possibly increase the heat created when cycling do to excessive friction. I didn't like the feel at all when cycling it by hand.

SO I tried what I'm going to give you directions to. Seals better than the stock oring with less friction than the 2 x 16mm oring. IMO it's the best of both worlds using what most people have readily available to them in there toolboxes.

First here's the O-rings side by side.
Left is 2 x 16mm
Center is Stock DP O-ring (old worn one)
Right is tank buna 70 duro
Here's how the bolts would look with the orings on them.
2x16mm
Stock (used and worn)
Tank without Teflon tape
Here's what you need. I didn't include the pic of the Tank O-ring, but that is what you will be using to put on the bolt after.
Wrap the Teflon tape so that the width of it goes completely into the slot. Helps to turn it sideways as in the pic.
Wrap only 2x and cut it.
This is what it should look like.
Put the Tank O-ring back on.
You can see how much the tank O-ring has stretched and protrudes.
Lube and your done. Doesn't matter what lube you use. Just use what you have.

You can do this with the stock O-ring in a pinch at the field. Just wrap the Teflon 1x instead of 2x.

The oring will hold the Teflon Tape in place. I have tried the mod and shot about 2 cases through it with no problems at all. Teflon Tape was still in the same place with no signs of coming out.
If you cycle your bolt by hand you will feel slightly more resistance than the stock O-ring, but not a lot. If there is too much friction, take some of the Teflon off of the bolt and then recheck how it feels when cycling.

EDIT: After much more paint I've only had to redo this mod 1 time. After letting my friend blast out the 25bps for fun and him fiddling with the velocity, the teflon started to unravel a bit. He over pressurized it and I had to fix a few things besides the #3 sail Teflon tape mod. After everything was put together, it's back to working great. For someone that's sceptical about this mod, I would suggest as xluben said, do it as a quick fix at the field if you don't have a replacement oring. The 2 x 16mm oring Oring Monkey uses would be a more dependable substitute than the stock sail oring. Since I haven't had any problems, besides what I just stated, it will be how I keep my Threshold. If the teflon does unravel it could be because you over pressurized it a bit. Redo the mod or replace the oring with the stock or 2 x 16mm oring. Don't continue to play with it. I'm not sure what, if anything, it'll do. I don't think it'll do any damage but I'm still testing so let me know if you encounter problems with it and I'll update this post.

Looks like a good solution if you're in trouble at the field. With the worn bolt
o-ring, I've also found that gobbing on the lube can get you through the day as
well.

I'm not sure I'd want to trust this as a long term solution, though. The
thought of teflon tape getting loose and causing more bolt leaks, or even
getting sucked into the noid is a little bit disconcerting.

Too bad DP just didn't use more commonly available o-rings. I bet if you tried
hard enough you may be able to get a G3/Threshold bolt/back cap to work
solely with tank size o-rings.

xluben, that would take lots of teflon tape. Tank o rings shoot through the threshold like its their job... stick to what DP offers. Believe me, i've tried in a pinch. You're fine for 30 shots, after that, say bye bye o ring

I thought of this for at the field kinda solution, but the Teflon doesn't move at all! The tank oring compresses it enough that the teflon can't come out. I've only done limited testing with it, but as I posted, Teflon had no signs of coming out or even moving. . If your really worried about it fraying, I guess you could twist the teflon a little bit while your wrapping it in the slot. Tank oring still in perfect condition too.

That's kinda how I thought about this. All DP would have to do is make the slot smaller and not as deep to accept a more standard oring size. I think they made it that way so that the oring can't dislodge from the slot since there is so much pressure it's holding back. Don't know if I would do this on the back cap oring, but it might work there also. I haven't had any problems with the back cap oring and really don't think it's prone to have any problems.
I guess if I ever have any problems with my back cap oring I might try this in a pinch, but don't think I would try to keep it as a permanent fix like I would the sail. The Sail oring slot seems less likely to have the teflon come out. Back cap oring has a small diameter slot, I think, and wouldn't stretch the tank oring enough. That's just in my mind's eye.

I had a very small piece come dislodged off my macro fitting once. It got into
my RAPS, and was enough to cause a persistent leak, that would not go
away even after I cleaned the visible piece off the piston o-ring. I had to
change the o-ring before the leak stopped.

Quote:

Originally Posted by meMYSELFnI

I thought of this for at the field kinda solution, but the Teflon doesn't move at all! The tank oring compresses it enough that the teflon can't come out. I've only done limited testing with it, but as I posted, Teflon had no signs of coming out or even moving. . If your really worried about it fraying, I guess you could twist the teflon a little bit while your wrapping it in the slot. Tank oring still in perfect condition too.

That may be true if you take your time and wrap the teflon around the bolt
nice and cleanly. But there's bound to be a 12 year old out there who will do
this in 5 minutes between games, get teflon tape sucked into their noid, and
then say that their gun is a broken piece of crap and will be pissed when DP
wants them to send it back, and then charge him for a new noid.

Quote:

Originally Posted by meMYSELFnI

That's kinda how I thought about this. All DP would have to do is make the slot smaller and not as deep to accept a more standard oring size. I think they made it that way so that the oring can't dislodge from the slot since there is so much pressure it's holding back. Don't know if I would do this on the back cap oring, but it might work there also. I haven't had any problems with the back cap oring and really don't think it's prone to have any problems.
I guess if I ever have any problems with my back cap oring I might try this in a pinch, but don't think I would try to keep it as a permanent fix like I would the sail. The Sail oring slot seems less likely to have the teflon come out. Back cap oring has a small diameter slot, I think, and wouldn't stretch the tank oring enough. That's just in my mind's eye.

The back cap is MUCH more prone to popping off problems. Nicad mentioned
this as one of his issues when designing/testing the HP Ion bolt. Since the
o-ring is in compression from the bolt, as well as feeling the force of the air,
and then when the bolt completely clears the back cap, the tendency is for
the o-ring to pop right off. I think that is how DP ended up with a 90 duro
that fits how it does. A tank o-ring might work OK for a while, but I doubt it
will last as long.

Not sure how shallow the groove could be made before the sail o-ring would
start having problems, but I would have to assume DP tried more than 1
configuration before deciding on this one.

I have a bunch of the 2 mm x 16 mm o-rings but I will not be seeing the field until July 19th. If anyone wants to test a few of the 2mm x 16mm o-rings, let me know so I can maybe send some out. Just so we have a wider range of samples. I know that O-ringmonkey is using the 2mm x 16mm in his o-ring kit instead of the stock 1.9mm x 15.8mm.

I have a bunch of the 2 mm x 16 mm o-rings but I will not be seeing the field until July 19th. If anyone wants to test a few of the 2mm x 16mm o-rings, let me know so I can maybe send some out. Just so we have a wider range of samples. I know that O-ringmonkey is using the 2mm x 16mm in his o-ring kit instead of the stock 1.9mm x 15.8mm.

i just purchased a kit from him , just so that i can have a bunch of the #3 . i hope they work if not im going to be pissed . he should had stated that .

Well I know my marker cycles with them in there but as meMYSELFnI stated, they do not move as easy by hand. I have also not had a chance to take any readings with paint with those o-rings. I plan to on 7/19 but that is a ways away. He had several testers use them before he came out with the kit and they worked so we should be ok. My advice would be not to use any swelling type lubes on it though. I guess we will see.

another wonderful idea. Sorry I didnt make myself clearer in an earlier post -

The way that the back cap on the threshold works does not permit any flexibility with regards to using different o-rings. The ID of the bolt stop/back cap oring is fairly small, while the OD is pretty large. If you were to increase the ID artificially, i.e. teflon taping and then use a tank o-ring, you will still likely run into trouble.

Also - I believe i run a 2mm x 16mm sail o-ring, i get a little heat, but nothing problematic. I purchased the 5x rebuild kit from oringmonkey and haven't had any problems since, however, as i mentioned before, i get a little heat.

Force some JB Weld into the groove and then file it down till the oring fits correctly

I actually thought of doing that to make a permanent solution to this problem, but wanted to see if I could get the tank oring to work as the sail oring before I made any permanent mod. The teflon works so well that I don't think you would NEED to do anything as permanent as jb weld.
I was thinking about maybe doing jb weld for the reg seat in the HPR. Do it like bedding a stock on a rifle with epoxy and just make sure to "release" the reg piston, so youdon't glue it together. Unfortunately I think a 14 yr old would glue them together if I were to make a more durable reg seat and do a tutorial.

Quote:

Originally Posted by ineasyi

I'm sorry guys what is this mod. for? Are we saying that by adding teflon tape the o-ring will stay on and not wear as fast?

Just want to make sure I understand.

The #3 sail oring tends to wear down enough not allow the bolt to cycle. If you look at an animation of the G3 or the Threshold you will notice that this oring allows the shift of pressure from the front of the bolt to the rear when the marker cycles. If the oring doesn't seal against the body the rear chamber equalizes the pressure in the front section of the bolt as soon as you pull the trigger. The noid cycles and the front chamber vents, but as soon as it does the rear chambers pressure equalizes by bypassing the oring, and the bolt remains stationary.
People with this problem will hear and feel the venting of the air as a "puff" on each trigger pull, but the bolt won't cycle. This solves that problem.

For those that are going to lube with slick honey or any other gel type lube. Just remember to lube your bolt once and while with dow33 or dow55 so that the excess lube vents through the noid to lube it. If you JUST use slickhoney the noid will become dry and wear on the orings. This could cause problems in the noid and ultimately make the noid piston stop cycling. I would suggest to lube with a paste type lube every few cases just to make sure that the noid gets lubed.